mechanics Flashcards
centre of mass
the point through which a single force acting on the body has no turning effect
couple
want an object to rotate but do not want its centre of mass to accelerate
average speed
total distance/ time
average velocity
total displacement/ time
what causes drag
partly by the friction between layers of air molecules near projectile surface
newtons 3rd law pairs
act on 2 separate bodies
same type of force
same magnitude
act along the same line
act in opposite direction
gradient for displacement time graph
velocity
tangent for displacement time graph
instantaneous velocity
gradient for velocity time graph
acceleration
tangent for velocity time graph
instantaneous acceleration
area under the graph for a velocity time graph
displacement
area under an acceleration time graph
velocity
in projectile motion, what is independent of one another
horizontal and vertical motion
terminal velocity
- weight > friction
-as v increases, fr increases , which causes the resultant force to decrease and acceleration decreases
- weight = friction (now have a terminal velocity)
-(parachute opens) - friction > weight , therefore, the person slows down
-weight = friction and get a new terminal velocity
impulse
force that causes a change in momentum
what is the area under a force time graph
impulse
what is the law of conservation of momentumn
in an isolated system, the total linear momentum is always conserved
elastic collisions
ek is conserved
inelastic collisions
ek is not conserved
explosions
ek is not conserved
principle of conservation
energy cant be created or destroyed
potential energy
the energy an object possess because of its position or configuration
constant
t = w
accel up
t > w
accel down
w > t
decel down
t > w
decel up
w > t
